The first recorded arrow shooting and aiming methods were found in ancient cave art where the images depict shooters with long bows held by an extended arm with the string drawn to their chest. This was apparently the conventional draw position for centuries up to and including Native Americans. Aiming from this position is natural in that it maximizes the use of the strong muscles of the arm, chest and shoulder. However, this position presents a significant challenge to aiming an arrow. Shooting from the chest creates a significant angle between the shooter's Line of Sight (LOS) with the target and the desired trajectory of the arrow from the bow. Determining the proper arrow pointing position for the trajectory to intersect the shooter's Line of Sight (LOS) at the desired point on the face of the target is complex with highly variable results. Shooting from this position places the axis of the arrow so far below the shooter's Line of Sight (LOS) that the shooter must rely heavily on instinctive aiming. This non-parallel aiming often described as parallax is counter intuitive and presents a negative impact on target acquisition, position repeatability and overall accuracy.
As early as the 5th century BC the crossbow was introduced as a less instinctive and more accurate method of aiming directly along the shaft of the arrow. This greatly improved the shooter's accuracy. The simple and intuitive nature of aiming directly along the shaft of the arrow meant that a novice with short and simple training could shoot a crossbow with accuracy comparable to a longbow in the hands of an extensively trained and well-practiced shooter. However, even with less accuracy the long bow remained as a weapon of choice for its reloading speed.
As the bow and arrow evolved from a weapon to use in a competitive sport where accuracy was more important than aiming speed the longbow shooters raised the draw point of the arrow nock up from the chest area to the jaw level making it much closer to the eye. Even though it took longer to position and aim with this new anchor point for the arrow string intersection and the draw hand it significantly reduced the parallax angle between the shooter's Line of Sight (LOS) and the axis of the arrow. Positioning the string and arrow intersection to a specific point on or near the shooter's face also made it more repeatable. The aiming errors were reduced improving shooting accuracy and reducing the training time required to become a skilled marksman.
The bow and arrow is no longer considered a significant weapon of war. Today it is recognized as a sport for the art of precision shooting of a bow and arrow at a target. However, the related sport of bow hunting continues to increase in popularity. As such, the demand for archery and bow hunting equipment has also increased. The archery industry has made significant technological advances for bow, arrow and aiming devices in response to this demand. This patent presents an Arrow Aiming Apparatus for Bowstring Releases that enables the next technological evolution to eliminate parallax by lowering the shooter's eye to aim directly along the shaft of the arrow in a manner that mimics aiming a rifle and provides more flexibility for rotating and tilting the bow while retaining the precision aim.
The following references disclose related sighting systems and are incorporated by reference herein:
U.S. Pat. No. 2,819,707 to Kayfes et al Jan. 14, 1958 for Bow String Drawing and Releasing Device,
U.S. Pat. No. 3,418,718 to Current et al Dec. 31, 1968 for Bow and Arrow Sight,
U.S. Pat. No. 3,859,733 to Cesnick Jan. 14, 1975 for Archery Peep Sight,
U.S. Pat. No. 3,266,149 to Powell Aug. 16, 1966 for Bow Scope Mount,
U.S. Pat. No. 7,325,319 B2 to Smith Feb. 5, 2008 for Arrow Mounted Sight,
U.S. Pat. No. 8,490,611 B2 Sep. 7, 2010 to Maynard for Distance Compensation Sight Device for Aiming an Archery Bow,
U.S. Pat. No. 6,134,793 to Sauers Oct. 14, 2000 for Bow Sight Alignment System,
U.S. Pat. No. 7,231,721,B2 to Minica et al. Jan. 19, 2007 Archery Laser Arrow,
U.S. Pat. No. 5,419,050 to Moore Sep. 30, 1995 Range Adjustable Laser Sight for Bows.
The bowstring release is a good example of these improvements to the archery aiming process as presented in U.S. Pat. No. 2,819,707. The bowstring release was introduced as an improved method to draw, hold and release the bowstring. The bowstring release eliminated the draw and hold stress created on the fingers by the strings of more powerful bows. It also provided a more repeatable way to secure and anchor the arrow nock for aiming and a smoother release of the string. The symmetrical grasp and release meant less lateral movement of the bowstring compared to sliding off the fingertips and therefore more accurate aiming. A variety of similar but related configurations have evolved into common use by archers.
Many sighting systems include a peep sight connected into the bowstring of an archery bow and at least one sight pin corresponding to a specific target distance U.S. Pat. No. 3,859,733. To aim, the archer normally looks through the peep sight at full draw and aligns the appropriate sight pin with the target. Pin sighting systems require the archer to know or estimate the distance to the target. Thus the accuracy of a shot made by a skilled archer is dependent on the ability to estimate distance to the target. If the distance to the target is known, a problem may still arise when the sight pin system does not have a pin preset for the current shooting distance. In this situation, the archer must shoot between the two pins closest to the current shooting distance thus sacrificing or losing additional accuracy.
The most common bow sights in use today incorporate peep sights into the bowstring and multiple forward pin sights mounted on the bow above the arrow rest. With this setup the shooter's Line of Sight (LOS) and the axis of the arrow still create a significant parallax angle depending on the pin distance above the arrow. Determining the proper correction and compensation for setting the location of the pins may be complex since it involves two independent variables, one for parallax and one for gravity compensation. The shooter's Line of Sight (LOS) and the axis of the arrow only cross at one point. Each pin represents a specific shooting distance from the target therefore the sight pin location, the shooters Line of Sight (LOS), and the trajectory of the arrow must cross exactly at the face of the target. In addition to being set to match a specific shooting distance the elevations of the multiple pins must be adjusted or preset to compensate for arrow fall or drop due to gravity over the horizontal distance traveled. In order for the arrow to successfully strike the desired spot on the target the arrow must be aligned to follow an arched path above the straight line as extended from the centerline axis of the arrow to the target. To determine the proper compensation for drop, multiple arrows are normally launched and measured as part of the pin setup.
This additional adjustment or compensation for gravity further complicates intuitive aiming and setting of the pins. The vertical location of each pin is normally established and preset during trial shooting or setup exercises. The elevation of each pin is positioned and used for arrow aiming at specific shooting distances. Establishing the proper angle and positioning is essentially a trial and error measured deviation process. The proper calibration and pin height are normally established by shooting multiple arrows at one distance from the target until achieving a close group or cluster of arrows in the target. This process is repeated at incremental distances from the target in an effort to simulate normal shooting situations for the shooter and the equipment.
The two primary compensation components of peephole and pin sights are 1) non parallel (parallax) aiming and 2) gravity (arrow drop or fall over extended distance).
1) Non Parallel (Parallax) Aiming
Peephole and pin sights are normally calibrated while shooting with the bow in the vertical position. This places the peephole, pin sight and arrow shaft in a plane that is parallel to the force of gravity. The shooter's Line of Sight (LOS) through the peep hole and around the sight pin aligns with the target. The position of the sighting pin is adjusted to make the shooter's Line of Sight (LOS) intersect the path of the arrow at the face of the target. The shooter's Line of Sight (LOS) and the projection line from the arrow to the target are not parallel therefore; the lines only intersect at one point.
2) Gravity (Arrow Drop or Fall Over Extended Shooting Distances)
Most sighting systems that involve pin sights must be used with the bow in a vertical or near vertical position. Up or downhill shooting complicates the settings for these systems. This invention avoids these complications and restrictions by rotating and tilting the Rear Sight in a manner that retains the height and elevation of the Rear Sight even when the bow is rotated or tilted.
The same peep and pin sights are also used to compensate for the fall of arrows over extended distance shots. The sighting pin is normally lowered an additional amount beyond the parallax adjusted position to raise the arrow path to offset the gravity fall. The pin height is determined by trial and error shooting at incremental distances.
The sighting pins are typically positioned in the plane of the bowstring and arrow thus limiting their use to aiming with the bow in a vertical position or parallel to the force of gravity. Gravity or arrow drop over distance is a key factor in setting the elevation of the sight pins. Therefore, for subsequent shooting of a bow equipped with peep and pin sights or any aiming system that includes non-parallel or parallax aiming, the bow must be held in approximately the same vertical plane that was used during pin setup. It also becomes more difficult for the shooter to see the pins through the peephole sight if the bow is tilted out of the setup plane. Rotating the bow introduces significant aiming errors. As the bow is rotated out of the vertical or setup plane the direction vector for gravity compensation also rotates and rather than elevating the arrow it acts to move the arrow laterally to the bow and out of line with the target. These limit and restrict a hunter's use of peep and pin sights because of the frequent need to position the bow out of the vertical plane to avoid tree limbs, bush and other obstacles. Therefore, when this occurs some hunters attempt to use the lowest pin setting which is normally used for near range shots. This removes drop compensation needed for longer shots. Off axis peep sight aiming is also awkward and limited by the hunter's ability to see through the sights and estimate the distance to the target. Without gravity compensation for longer shots the hunters are left to estimate the distance and drop or just, “aim high”, and hope for good luck. The peep and pin aiming process begins with the shooter selecting the appropriate pin based on shooting distance from the target. The shooter then aligns the rear peep sight, the selected pin, and the target. This method of aiming may provide consistent results when properly setup and used by experienced archers. However, for less experienced shooters this non intuitive method of aiming often results in optical confusion and sighting inconsistencies since the shooter's Line of Sight (LOS) is not parallel to the arrow shaft. This visual aberration is often referred to as parallax. As a further complication even experienced hunters sometimes complain that selecting the proper pin during a rushed aiming process can be disruptive and confusing often resulting in poor target acquisition.
U.S. Pat. No. 7,231,721 B2 addresses this issue by proposing to mount a small laser into the arrowhead. This would enable alignment of the arrow direct with the target thus eliminating the parallax. However, this approach would require alteration of each arrow and add weight for the laser and power source to the arrow. Lasers work best in dark or low light conditions. Their use may also be restricted by rules and regional regulations. Viewing a low power laser spot at a distance in full daylight can be difficult at best. Most state of the art bow sights rely on either laser or optical sights for alignment. The lasers provide extremely accurate pointing accuracy along the beam axis. However, conventional mounting of the laser to the bow again results in parallax aiming where the laser beam and the arrow path only cross at one point—U.S. Pat. No. 5,419,050. For longer shots that include drop compensation lasers, like peep and pin sights, must also be aimed in the same position that was used to establish the parallax angle during trial shooting and setup. This restricts hunters from tilting the bow out of the setup position to avoid obstacles. Bow mounted lasers, like pin and peep sights, create a different parallax angle at each distance therefore requiring elevation correction of the sight pin even for close shooting distances that require no gravity compensation. They likewise require trial and error shooting at incremental distances from the target to determine the best laser angle height setting for each distance. Laser sights work best in low light shooting environments. Bright sunshine and/or dark targets absorb the laser light making it extremely difficult if not impossible to see the projected dots.
Optical sights primarily depend on pin alignment sights or scopes. Because they are attached to the bow they too result in opportunities for parallax aiming errors. Both peep and laser sights attach to the bow. This means that the shooter is actually aiming the bow as an indirect means to aim the arrow. Any inconsistencies between the arrow and the bow may contribute to poor target acquisition.